Some BlackBerry users in North America and the United Kingdom experienced data outages Monday and yesterday on Wi-Fi-equipped BlackBerries when not connected to Wi-Fi, according to user groups and some U.S. carriers.

The problems appeared to have ended late yesterday, but BlackBerry maker Research In Motion Ltd. (RIM) did not respond to inquiries or offer any immediate comments about the outage today. RIM has been criticized in the past for not reporting or explaining outages, although it did offer a fairly lengthy explanation for a December data outage related to a BlackBerry Messenger update.

"Of all the RIM outages in recent years, the only one where they issued any official explanation was the Dec. 23 one," said Joe Sanders, a self-described "BlackBerry geek" who regularly communicates about BlackBerry matters with other users nationwide as a moderator on BlackBerryforum.com. He reported this week's outage on the Data Outages forum.

Sanders called this week's outages relatively minor compared to the December problem. "It wasn't everyone and not major, but there was a lot of complaining," said Sanders, who runs Master Image, a printing operation in Birmingham, Ala.

Data Outage News reported yesterday that the outages generally affected Wi-Fi-enabled BlackBerry devices when they were out of range of a Wi-Fi signal. The site noted that the affected users were connected via both BlackBerry Enterprise Server and BlackBerry Internet Service.

Sanders, who spoke to a number of users, said that voice and text services were unaffected. He also said at least four carriers in the U.S. had the problem, including his own carrier, AT&T, as well as T-Mobile USA, Verizon Wireless and Unicel, a small carrier. A Verizon Wireless spokesman, however, said that Verizon had no BlackBerry outages, while an AT&T spokeswoman said a small number of customers might have been affected. Both referred further questions to RIM.

Sanders said he only noticed an outage on his BlackBerry Storm when he left a Wi-Fi zone and couldn't get data on the AT&T network.

He said it would be helpful if RIM communicated more about what happened but said users are accustomed to minor outages and can usually find voice or text to use as a backup. "It's not a problem [if RIM doesn't report outages], because I know about the outage anyway," he said.